Analgesics are drugs which relieve pain and they act to relieve pain by elevating the pain threshold of a patient in need of pain relief. One group of analgesic drugs is the opiates. The opiate group of analgesics is among the most powerfully acting and clinically useful drugs for the relief of pain. The term "opiate" was once used to designate analgesic drugs derived from opium, including morphine, codeine and synthetic congeners of morphine. With the development of totally synthetic drugs with morphine-like actions, the word opioid is used to refer to all drugs, both natural and synthetic, with morphine-like actions. The term "narcotic" as associated with the opioids refers to the physical dependence accompanying the use of these drugs, and with their increasing use it refers to opioid substances that cause dependence.
In addition to their many important medical uses, the opioid drugs are employed commonly for illicit purposes, including emotional, psychological, euphoric, hallucinogenic, depressive and psychedelic experiences. These purposes, and the physical dependence accompanying the administration of these drugs, have led to drug abuse. Drug abuse has become, for many habituates, a way of life. To a rapidly growing segment of the world population use of these drugs is a vogue often seen as fashionable. While these drugs are a necessary part of modern medicine, it would be highly desirable to provide a novel drug delivery system and a novel composition of matter that do not possess drug abuse potential, and thereby seek to lessen the incidence of their abuse and their illicit use.